JP2006341231A - Control method of amount of ink jet printer discharge and its device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink jet printer causing no complication of a print head control system, excessive amount of information, nor increase of cost, without depending on adjustment of applied voltage to respective nozzles, by correctly uniformizing a discharge state of ink from each nozzle. <P>SOLUTION: This ink jet printer is provided with a coating object (glass substrate) 2 having ink non-absorbing property, on which a film is formed by discharging ink from multiple nozzles 4 of the print head 3; a film thickness measuring means 6 measuring a thickness of film B formed on the coating object 2 in relation to the ink discharge positions of the respective nozzles 4; and a discharge amount correction means 8 increasingly or decreasingly correcting the discharged amount of ink from the nozzles 4, based on the difference between the film thickness B at the ink discharge position of each nozzle 4 measured by the film thickness measuring means 6 and a target film thickness Ba. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method and apparatus for controlling the amount of ink discharged from an ink jet printer, and more particularly, to determine the amount of ink discharged from a plurality of nozzles in a print head of the printer on the object to be coated. It is related with the technique for equalizing between.

  In recent years, in addition to performing printing with an ink jet printer on a substrate made of paper, cloth, resin, ceramic, or the like, when forming an alignment film on a transparent glass substrate in a liquid crystal display device or the like, Inkjet printers have come to be used even when a color filter is applied on a transparent glass substrate in a display. More specifically, in the case of a liquid crystal display device, a transparent PI ink (transparent polyimide ink) or a transparent UV ink, which is a material of the alignment film, is applied by being discharged onto a glass substrate (for example, Patent Document 1). In the case of an organic EL display device, for example, a transparent UV ink, which is a coating material, is applied by being discharged onto a glass substrate.

  In this case, the ejection mode of the ink ejected from the plurality of nozzles in the print head of the ink jet printer is preferably uniform among the nozzles. For example, in the case of a printed matter mainly composed of colors, Ink was ejected on an object to be coated having ink absorption properties (ink absorbability) after consideration was given to uniform color shading from each nozzle. In this way, it is possible to easily achieve uniform color shading on an ink-absorbing object if the discharge state of ink droplets from each nozzle is reasonably uniform. is there.

  However, forming a thin film having a uniform film thickness on an object to be coated that does not absorb ink (non-ink-absorbing property), for example, the above-described glass substrate, depends on the ink jet printer currently used. A great deal of difficulty will be required. That is, it is particularly difficult to form a thin film having a uniform film thickness of less than 1 μm on an object to be coated having this kind of ink non-absorbing property. In order to obtain a film thickness, when ink is ejected as droplets from each nozzle, it is necessary to accurately improve the ejection state of the ink droplets.

  Therefore, by finely adjusting the applied voltage of each nozzle in the print head of the ink jet printer (drive voltage that causes pressure fluctuation in the pressure chamber leading to the opening of each nozzle), the ejection state of the ink droplets ejected from each nozzle can be changed. Attempts have been made to form a film having a uniform thickness on an object to be coated, which is appropriately uniform. According to the following Patent Document 2, it is disclosed that the applied voltage (drive voltage) is corrected in order to adjust the ejection speed of the ink droplets from the nozzles.

JP 2001-42330 A JP 2003-191467 A

  By the way, in recent years, for example, due to an increase in the size of a glass substrate, it has become necessary to increase the application width of an ink by an ink jet printer and to increase the application length, and to shorten the application time. The actual situation is also demanded. Under such circumstances, even if it is attempted to adjust the voltage applied to each nozzle of the print head in order to make the film thickness uniform as described above, various problems are associated with the adjustment.

  In other words, in order to widen the ink application width, the print head itself must also be widened to greatly increase the number of nozzles, and the print head becomes of course extremely expensive. The control system for controlling this is also complicated and expensive. Further, since the amount of information in the control system becomes enormous, there is a problem that the ink application speed by each nozzle is unduly lowered.

  Moreover, even if the applied voltage of each nozzle in an existing ink jet printer is individually adjusted to make the application of ink droplets uniform, the accuracy of the applied voltage is limited and it is difficult to achieve sufficient uniformity. I must say that there is. That is, for example, the uniformity (variation) of the alignment film formed on the glass substrate for the above-described liquid crystal display device is required to be about 2%. The droplet discharge accuracy is about 5%. Therefore, to adjust the applied voltage of each nozzle in such an ink jet printer so that the film uniformity is around 2%, it is necessary to improve the accuracy (resolution) of the applied voltage. However, even if it is realized, the control system is further complicated, the amount of information is excessive, and the ink application speed is further reduced.

  The present invention has been made in view of the above circumstances, and accurately and uniformly discharges ink on an object to be discharged from each nozzle without being affected by the adjustment accuracy of the voltage applied to each nozzle. It is a technical problem to provide an inkjet printer that does not cause a complicated print head control system, an excessive amount of information, and an increase in cost.

  In order to solve the above technical problem, a method for controlling the ejection amount of an ink jet printer according to the present invention comprises ejecting ink from a plurality of nozzles of a print head onto an object to be coated with ink non-absorbability. A film forming step for forming a film on the object to be coated; a film thickness measuring step for measuring the film thickness of the film formed on the object to be coated in the film forming process in relation to the ink discharge position of each nozzle; And a discharge amount correction step for correcting the ink discharge amount from each nozzle to increase or decrease based on the difference between the film thickness at the ink discharge position of each nozzle measured in the film thickness measurement step and the target film thickness. Characterized.

  According to such a method, an object to be coated (for example, a glass substrate) having non-ink-absorbing properties is effectively used, and a film is formed by actually ejecting ink thereon, and further the film thickness of the film Is measured in relation to the ink discharge position of each nozzle, and the difference between the actual film thickness as the measurement result and the target film thickness as the target value is determined for each ink discharge position of each nozzle. The ink discharge amount from the nozzles (in other words, the ink discharge amount on the coating object discharged from each nozzle) is corrected to increase or decrease. Therefore, the ink discharge amount variation from each nozzle is detected in advance, the discharge amount from each nozzle is corrected so that the variation is eliminated, and the film is actually formed by the print head. Is possible. As a result, the ejection amount of the ink ejected from each nozzle on the coated object can be reduced without unduly affecting the control system of the print head and the amount of information and without preventing the ink application time from being shortened. It becomes possible to make the ink uniform, and it becomes possible to uniformly apply the ink while responding to the recent demand for a wider application width. In addition, when actually applying after correcting the ink discharge amount from each nozzle using this method, an alignment film is formed on a transparent glass substrate in a liquid crystal display device or the like, or an organic EL display is used. For example, a case where a transparent UV ink as a coating material is applied onto a transparent glass substrate in a container is particularly effective, but the case where printing is performed on a substrate made of paper, cloth, resin, ceramic, or the like is excluded. Do not mean.

  In this case, it is preferable that correction data for increasing / decreasing the ink discharge amount of each nozzle is generated in the discharge amount correction step, and the correction data is stored.

  In this way, the ink ejection amount from each nozzle is corrected to increase or decrease in accordance with the stored correction data. Therefore, when the ink is actually applied by the print head, the storage means (storage unit) From this, the correction data is read out, each nozzle is adjusted, and the ink discharge amount is corrected, so that the speed and convenience of processing can be improved. In addition, for example, when a plurality of print heads having a plurality of nozzles are arranged to form a single ink jet printer, the correction value of the ink discharge amount at each nozzle is stored as correction data. Even if the head is replaced or rearranged, the amount of ink that has been accurately corrected can always be ejected from each nozzle. Moreover, even if the ejection characteristics of each nozzle change due to secular change or secular change, if correction data is newly created and stored, it is only necessary to update the correction data. Appropriate ink ejection based on the correction data can be performed without any trouble.

  In the discharge amount correction step, it is preferable to change the distribution of the number of droplets on the application object of ink discharged from each nozzle.

  In this way, the increase / decrease correction of the ink discharge amount at each nozzle is performed by changing the distribution of the number of droplets on the coating object of the ink discharged from each nozzle. You can enjoy the advantage of being accurate.

  On the other hand, an ejection amount control device for an ink jet printer according to the present invention, which was created to solve the above technical problem, is a non-ink ink in which a film is formed on the surface by ejecting ink from a plurality of nozzles of a print head. A film thickness measuring means for measuring the film thickness of an object to be coated having absorptivity and the film formed on the film to be coated in relation to the ink discharge position of each nozzle; and the film thickness measuring means. Further, the present invention is characterized by comprising discharge amount correction means for increasing or decreasing the discharge amount of ink from each nozzle based on the difference between the film thickness at the ink discharge position of each nozzle and the target film thickness.

  According to such an apparatus, a film is formed by ejecting ink on an object to be coated (for example, a glass substrate) having non-ink-absorbing properties. After measurement in relation to the ink ejection position of the nozzle, the difference between the actual film thickness as the measurement result and the target film thickness as the target value is determined by the operation of the ejection amount correction means. It is determined for each position, and the amount of ink discharged from each nozzle (in other words, the amount of ink discharged on the coating material discharged from each nozzle) is corrected to increase or decrease. By performing such correction, it is possible to obtain the same effects as the contents already described with respect to the matters corresponding thereto. In addition, what is to be actually applied after the ink ejection amount from each nozzle is corrected using this apparatus is the same as already described.

  In this case, it is preferable that the apparatus further includes a storage unit that stores correction data for the discharge amount correction unit to increase or decrease the discharge amount of each ink.

  Even in this case, the ink discharge amount from each nozzle is corrected to increase or decrease in accordance with the correction data stored in the storage means. The same effect can be obtained.

  Further, it is preferable that a plurality of print heads having the plurality of nozzles are arranged adjacent to each other along the nozzle arrangement direction.

  In this way, even when the coating width of the ink is increased with the increase in the size of the object to be coated (for example, a glass substrate for a liquid crystal display device) in recent years, the uniformity can be achieved in a short time. Ink can be appropriately discharged onto the object to be coated without being obstructed.

  As described above, according to the present invention, a film is formed by ejecting ink onto an object to be coated that does not absorb ink, and the film thickness of the film is measured in relation to the ink ejection position of each nozzle. After that, the difference between the actual film thickness that is the measurement result and the target film thickness that is the target value is calculated for each ink discharge position of each nozzle, and the ink discharge amount from each nozzle can be corrected to increase or decrease. As a result, the ink ejection from the nozzles on the object to be coated without unduly adversely affecting the print head control system and the amount of information and without hindering the shortening of the ink application time. The amount can be made uniform, and it becomes possible to uniformly apply the ink in response to the recent demand for a wide application width.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a schematic configuration diagram including main components of an ejection amount control device for an inkjet printer according to an embodiment of the present invention. As shown in the figure, the ejection amount control device 1 controls the amount of ink ejected from a transparent glass substrate 2 for a liquid crystal display device having ink non-absorbability and a plurality of nozzles 4 of a print head 3. A controller 5 for controlling, and a film thickness measuring means 6 for measuring the film thickness of the film formed on the glass substrate 2 by discharging ink from the print head 3 in relation to the discharge position of each nozzle 4. Yes. Further, the discharge amount control device 1 includes a storage unit 7 for storing correction data corresponding to each difference between the film thickness at the ink discharge position of each nozzle 4 measured by the film thickness measuring unit 6 and the target film thickness. Further, it includes a discharge amount correction unit 8 that reads the correction data stored in the storage unit 7 and corrects the discharge amount of ink from each nozzle 4 of the print head 3 based on the controller 5.

  A more specific configuration of the discharge amount control apparatus 1 having such a configuration and its work procedure will be described in detail below.

  As shown in FIG. 2, in the ink jet printer according to the present embodiment, a plurality (four in the illustrated example) of print heads 3 having a plurality of nozzles are arranged along the nozzle arrangement direction. As a work procedure, first, the computer 9 calculates the voltage applied to the print head 3 from the number of ink droplets corresponding to the target film thickness (target value of the film thickness), and uses this calculated value as a command signal to the controller 5. By sending out, a signal indicating the applied voltage is sent from the controller 5 to the print head 3 through the applied voltage line 10, whereby the ejection amount of ink ejected from each nozzle of the print head 3 is adjusted. Further, the controller 5 sends a signal indicating from which nozzle in which print head 3 a droplet is ejected through the ejection data line 11.

  Under such a state, ink droplets are discharged onto the glass substrate 2 from all the nozzles of all the print heads 3 so that the discharge amount adjusted as described above is obtained. In this case, the ink is ejected onto the glass substrate 2 so that the droplets A ejected from adjacent nozzles are alternately displaced by 1/2 pitch as shown in FIG. The ink droplet A having 50% of the total discharge amount is landed on the glass substrate 2 in a state as illustrated (this state is referred to as a 50% ejection pattern). In contrast to this, as shown in FIG. 4, when the droplets A discharged from the adjacent nozzles do not cause a pitch shift and are not missing, the discharge amount is 100% by all the nozzles. Corresponding ink droplets A are in the state shown in the figure and land on the object to be coated (this state is referred to as a 100% ejection pattern).

  Then, as shown in FIG. 5, when the ejection of the ink from the four print heads 3 is completed with the 50% ejection pattern with the movement of the glass substrate 2 in the arrow X direction, In other words, a thin film is formed in the first to fourth application regions A1, A2, A3, A4 over a wide application width T. Thereafter, as shown in FIG. 6, the film thickness measuring means 6 is used to form a film along the nozzle arrangement direction from the start end of the first application area A1 having the application width T1 to the end of the fourth application area A4. The thickness is measured, and it is determined whether the film thickness at the discharge position of which nozzle 4 of which print head 3 is thin or thick.

  FIG. 7 is a vertical cross-sectional view showing the formation state of the film B in the first application region A1 having the application width T1. As shown in the figure, when the film B in the first application region A1 has an insufficient film thickness portion Bx or an excessive film thickness portion By with respect to the target film thickness Ba described above, it corresponds to these. The number of ink droplets from the nozzle is corrected to increase or decrease. Specifically, for the nozzle corresponding to the insufficient film thickness portion Bx, as in the distribution state of the droplet A on the glass substrate 2 shown in FIG. 8, the number of ink droplets ejected from the nozzle is indicated by a symbol. For the nozzle corresponding to the excessive film thickness portion By, the number of droplets of ink ejected from the nozzle is increased by the droplet amount indicated by Ax. (Referred to as thinning). Note that such correction of the distribution state of the droplets A on the glass substrate 2 is performed in the entire first to fourth application areas A1 to A4.

  By performing the correction as described above, the insufficient film thickness portion Bx and the excessive film thickness portion By approach the target film thickness Ba as shown in FIG. Then, if necessary, the operations described with reference to FIGS. 4 to 8 are repeatedly performed, thereby bringing the insufficient film thickness portion Bx and the excessive film thickness portion By as close as possible to the target film thickness Ba. Thereby, the uniformity of the film thickness in all the areas of the first to fourth application areas A1 to A4 on the glass substrate 2 is improved.

  Thereafter, the distribution of the number of ink droplets on the glass substrate 2 for all the nozzles of all the print heads 3 including the nozzles that have been corrected to increase or decrease the number of ink droplets on the glass substrate 2 as described above. The ejection pattern shown is stored as correction data in the storage means 7 built in the computer 9 through the data write line 12 shown in FIG. In this way, for example, when a plurality of print heads 3 are used in a different arrangement order, the stored correction data is read by the discharge amount correction means 8 built in the computer 9, and this As shown in FIG. 11, by executing writing 13 to each print head 3 from the discharge amount correcting means 8, all the print heads 3 can easily apply a uniform film with high accuracy.

  Thus, based on the correction data, the number of ink droplets from all the nozzles of all the print heads 3 (the number of ink droplets corresponding to the distribution state of the droplets on the glass substrate 2 based on the correction data) is obtained. After the setting, the inkjet printer mainly applies an alignment film on a transparent glass substrate for a liquid crystal display device, and a color filter on a transparent glass substrate for an organic EL display. Further, printing on a substrate made of paper, cloth, resin, ceramic, or the like can also be performed.

It is a schematic block diagram of the discharge amount control apparatus of the inkjet printer which concerns on embodiment of this invention. It is the schematic which shows the specific structure of the said discharge amount control apparatus. FIG. 3 is a schematic plan view showing a landing state of ink droplets ejected from the ejection amount control device. FIG. 3 is a schematic plan view showing a landing state of ink droplets ejected from the ejection amount control device. It is the schematic which shows the state which formed the film | membrane on the glass substrate by the said discharge amount control apparatus. It is the schematic which shows the state which is measuring the film thickness of the film | membrane formed on the glass substrate with the said discharge amount control apparatus. It is a longitudinal cross-sectional view which shows the film | membrane formed on the glass substrate by the said discharge amount control apparatus. FIG. 2 is a schematic plan view showing a landing state of ink droplets ejected after correction by the ejection amount control device. It is a longitudinal cross-sectional view which shows the film | membrane formed on the glass substrate after correction | amendment by the said discharge amount control apparatus. It is the schematic which shows operation | movement of the said discharge amount control apparatus. It is the schematic which shows operation | movement of the said discharge amount control apparatus.

Explanation of symbols

1 Inkjet printer discharge rate control device 2 Glass substrate (to be coated)
3 Print head 4 Nozzle 6 Film thickness measurement means 7 Storage means 8 Discharge amount control means A Droplet B Film Ba Target film thickness

Claims (6)

  A film forming step of forming a film on the coating object by discharging ink from a plurality of nozzles of the print head onto the coating object having non-ink-absorbing properties, and forming on the coating object in the film forming process A film thickness measurement process for measuring the film thickness of the film formed in relation to the ink discharge position of each nozzle, and the film thickness at the ink discharge position of each nozzle measured in the film thickness measurement process and the target film thickness An ejection amount control method for an ink jet printer, comprising: an ejection amount correction step for increasing / decreasing an ejection amount of ink from each nozzle based on a difference.   The discharge amount control of an ink jet printer according to claim 1, wherein correction data for increasing or decreasing the ink discharge amount of each nozzle is created in the discharge amount correction step, and the correction data is stored. Method.   3. The method of controlling an ejection amount of an ink jet printer according to claim 1 or 2, wherein, in the ejection amount correcting step, the distribution of the number of droplets on the coating object of the ink ejected from each nozzle is changed.   The object to be coated with ink non-absorbing property in which a film is formed on the surface by ejecting ink from a plurality of nozzles of the print head, and the film thickness of the film formed on the object to be coated are determined for each nozzle. Based on the difference between the film thickness measurement means measured in relation to the ink discharge position and the film thickness at the ink discharge position of each nozzle measured by the film thickness measurement means and the target film thickness, A discharge amount control apparatus for an ink jet printer, comprising discharge amount correction means for increasing or decreasing a discharge amount.   5. The discharge amount control apparatus for an ink jet printer according to claim 4, further comprising storage means for storing correction data for the discharge amount correction means to increase or decrease the discharge amount of each ink.   6. The discharge amount control method for an ink jet printer according to claim 4, wherein a plurality of print heads having the plurality of nozzles are arranged adjacent to each other along the nozzle arrangement direction.

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